Normal Pressure Hydrocephalus

The syndrome of normal pressure hydrocephalus (NPH) was described in 1965 by Hakim and Adams. The clinical presentation consists of a gait disturbance dementia and incontinence, accompanied by cerebral ventricular enlargement with a normal cerebrospinal fluid pressure. In the Hakim and Adams series of three patients, there was improvement with a shunting procedure. Enthusiasm for another potentially correctable dementia led to broad application of diagnostic criteria; many patients with dementia and prominent ventricular enlargement underwent surgery, with variable, often unsatisfactory, response. Subsequently, there was an attempt to define physiologically and tighten the ·original diagnostic criteria. Emphasis was focused on the gait abnormality and an attempt was made to demonstrate a CSF absorptive defect which was produced by a block within the basal cisterns. In a syndrome with widely ranging diagnostic criteria, it was not surprising that there was a variable response to therapy in the reported series. Individual series reported clinical improvement ranging from IO to 80 percent of patients (median 40 %) . Frequently, in patients who vigorously fulfilled diagnostic criteria, there was no improvement following shunting. Who should be considered for shunting? No single clinical feature or diagnostic procedure can determine this selection or predict improvement as a result of shunting. The frequent occurrence of significant, even life-threatening, complications in these patients dictates that the physician's major responsibility is to select those patients who are most likely to benefit from the procedure as well as those patients who will tolerate it best. The selection must be made after careful consideration of the history and clinical status of each patient